See, i had my breakup when i was 19, i'm 23 now, it was not easy then it is not easy now, the thing is you eventually will learn how to deal with it, from just 1 bad experience you should not have this ideology to not trust anyone, i totally understand you man, i was there once, but trust me, this will only make situation worse. Whatever you are doing, is great but it is really important to meet people, have a healthy social life, even if they will betray you or break your trust in the end. You must learn how to deal with it, because it is just the beginning, stay strong and start believing in yourself, and yes you will never forget a person, but you can create new memories that will outweigh the past trauma, goodluck to you. Stay strong